HALEMAUMAU, Hawaii  Scientists, civil defense and Hawaii Volcanoes National Park officials are grappling with a new set of problems as the summit of Kilauea volcano pumps out an unprecedented amount of gas and volcanic ash.

The trade winds have helpfully pushed pollutants away from most populated areas since Kilauea nearly doubled its gas emissions earlier this month, but it is only a matter of time until the winds shift.

When that happens, higher levels of sulfur dioxide and other particles may be blown into nearby communities that are home to about 10,000 people, posing a potential health threat as far as 20 miles away from the volcano. People with respiratory problems such as asthma, bronchitis and emphysema would be particularly at risk.

The unexpected increase in sulfur dioxide production at the summit of the volcano has officials at the Hawaii Department of Health scrambling to develop new guidelines to determine when communities may be at risk from short-term spikes in the emissions, and how great those risks may be.

Those guidelines aren't expected to be completed until next week.

Big Island Mayor Harry Kim acknowledged Wednesday that scenarios are being studied that could include evacuations of the 800 workers at Hawaii Volcanoes National Park and the surrounding area if the air quality deteriorates dramatically.

"The worst-case scenario obviously would be if in areas of the park the (sulfur dioxide) reaches a level that we will advise evacuation of all people," he said. "Hopefully that will not be, but obviously that is a scenario based on wind conditions that could be for the areas abutting the national park."

Pu'u 'O'o on Kilauea's East Rift Zone has been pumping out about 2,000 metric tons of sulfur dioxide per day for years, while only about 200 tons per day was being released at Halemaumau at the summit. The sulfur dioxide emissions from the summit began to climb late last year, and by March 13 had climbed to record levels of 2,000 tons per day.

The emissions at Pu'u 'O'o have held steady since then, while the gas released from Halemaumau has ranged from 600 to 2,500 tons over the last few days. Overall, the emissions from the volcano have roughly doubled, scientists said.

A seven-member team assembled by the National Park Service has been at the park for a week helping parks officials plan for various contingencies, and the Federal Aviation Administration has closed the air space below 4,000 feet for three miles around the vent because of the risk the ash and smoke present to aircraft.

In Wood Valley, within the 20-mile radius around the volcano, the effects of the change in the eruption are obvious. A layer of ash has been dusting the hoods of vehicles and other surfaces, and when the wind is wrong, the vog (volcanic smog consisting of sulfur dioxide particles) is thick.

Claudia McCall, who operates a cut-flower farm with her husband in Wood Valley, said the fumes and vog have damaged leaves on some of her crops, and said her roses seem particularly sensitive. If the summit emissions continue, she said, she may have to give up on roses, which will severely hurt her business.

"I'm actually more concerned with the health of the people," she said of the fumes. "When you can taste it, you know it's not good to breathe it."

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The home of Big Island resident Jean Olson sits atop of an active lava field, with volcanic gas billowing in the background on March 19 in Kalapana, Hawaii. Olson's home is built atop the 1990 lava flow which destroyed the town of Kalapana.

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